Clipping cross section shader

[Cameron-Micka]

Forked from: microsoft/MixedRealityToolkit-Unity#11058

Describe the problem

As shown in the figure, we can see through the cross section, usually it's good but if the model represents a solid part, it looks then not very 'nature'.

It would be perfect if we have an option to render the cross section with the material from the clipped part. Like the figure here (which is from CAD software)

Describe the solution you'd like

Add an option in ClippingPlane (and Box, Sphere) script to choose whether to treat the clipped game object as solid. if true then render the cross section with its body material.

Describe alternatives you've considered

Add a new shader for clipping with this feature.

Maybe there is already a solution that I did not find, if so please let me know about it.
Thank you in advance.